try to execute kafka 0.7.2 and got such exception:log4j:WARN No appenders could be found for logger(org.I0Itec.zkclient.ZkConnection).log4j:WARN Please initialize the log4j system properly.Exception in thread "main" java.lang.NumberFormatException: null at java.lang.Integer.parseInt(Integer.java:417) at java.lang.Integer.parseInt(Integer.java:499) at scala.collection.immutable.StringLike$class.toInt(StringLike.scala:208) at scala.collection.immutable.StringOps.toInt(StringOps.scala:31) atkafka.producer.ZKBrokerPartitionInfo$$anonfun$kafka$producer$ZKBrokerPartitionInfo$$getZKTopicPartitionInfo$1$$anonfun$5.apply(ZKBrokerPartitionInfo.scala:167) atkafka.producer.ZKBrokerPartitionInfo$$anonfun$kafka$producer$ZKBrokerPartitionInfo$$getZKTopicPartitionInfo$1$$anonfun$5.apply(ZKBrokerPartitionInfo.scala:167) atscala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:206) atscala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:206) at scala.collection.Iterator$class.foreach(Iterator.scala:631) atscala.collection.JavaConversions$JIteratorWrapper.foreach(JavaConversions.scala:549) at scala.collection.IterableLike$class.foreach(IterableLike.scala:79) atscala.collection.JavaConversions$JListWrapper.foreach(JavaConversions.scala:596) at scala.collection.TraversableLike$class.map(TraversableLike.scala:206) atscala.collection.JavaConversions$JListWrapper.map(JavaConversions.scala:596) atkafka.producer.ZKBrokerPartitionInfo$$anonfun$kafka$producer$ZKBrokerPartitionInfo$$getZKTopicPartitionInfo$1.apply(ZKBrokerPartitionInfo.scala:167) atkafka.producer.ZKBrokerPartitionInfo$$anonfun$kafka$producer$ZKBrokerPartitionInfo$$getZKTopicPartitionInfo$1.apply(ZKBrokerPartitionInfo.scala:163) at scala.collection.Iterator$class.foreach(Iterator.scala:631) atscala.collection.JavaConversions$JIteratorWrapper.foreach(JavaConversions.scala:549) at scala.collection.IterableLike$class.foreach(IterableLike.scala:79) atscala.collection.JavaConversions$JListWrapper.foreach(JavaConversions.scala:596) atkafka.producer.ZKBrokerPartitionInfo.kafka$producer$ZKBrokerPartitionInfo$$getZKTopicPartitionInfo(ZKBrokerPartitionInfo.scala:163) atkafka.producer.ZKBrokerPartitionInfo.<init>(ZKBrokerPartitionInfo.scala:65) at kafka.producer.Producer.<init>(Producer.scala:47) at kafka.javaapi.producer.Producer.<init>(Producer.scala:33) at kafka.javaapi.producer.Producer.<init>(Producer.scala:40) at kafka.example.Producer.main(Producer.java:66)Disconnected from the target VM, address: '127.0.0.1:49086', transport:'socket'

Yes , I resolve this by changing a configuration path in zookeeperproperties dataDir=/tmp/zookeeper. I made scala code debug and got that Ihave cuple of topics from previous executions. One of the topic cause theexception. By the way : do I understand correct that kafka serialize the data ondisc?What is the serialization polisy?In case I want to delete / remove topic how can I do in using API?